The chunkah package is not yet available in CentOS Stream/RHEL,
so having it in the shared standard/manifest.yaml breaks backports
(see https://gitlab.com/redhat/centos-stream/containers/bootc/-/merge_requests/1034).
Move it to the top-level standard.yaml which is Fedora-specific and
not backported.
Assisted-by: OpenCode (Claude Opus 4.6)
It's confusing right now how the manifest names differ across
fedora-bootc, centos-bootc and rhel-bootc. Both rhel-bootc and
centos-bootc only use "bare" names like `minimal`, and `standard`, while
fedora-bootc prefixes everything with `fedora-`.
For FCOS/SCOS/RHCOS, it would be beneficial to maintain the same naming
across all of those.
Let's just match the naming here to the "bare" version. But add symlinks
so that we don't break the old names (but note that being symlinks, they
will no longer show up in `bootc-base-imagectl list`).
